This invention relates to a blood collection assembly incorporating a microcollection container. The invention is an improvement over the collection assembly described and claimed in U.S. Pat. No. 4,397,318, issued Aug. 9, 1983, which is hereby incorporated by reference in its entirety. Reference should be made to that patent for background information concerning the teachings of the invention here. The earlier patent involved the use of a scoop collector for connection to a blood microcollection container for engaging a puncture wound to obtain a blood sample from an individual for subsequent examination of that sample for the determination of the presence or absence of some disease or other problem in a patient. The scooptype blood collection device provides a substantially larger engaging surface for engaging the puncture for collecting the blood, and a substantially larger transfer surface for rapidly transferring the blood from the collector into the microcollection container. Because of the relatively large engaging surface for engaging the puncture wound, the arrangement does not require a precise positioning of the scoop engaging surface in order to initiate and rapidly transfer a quantity of blood to the microcollection container.
As will be appreciated by practitioners-in-the-art, recent advancements in analytical instrumentation have made it possible to carry out a variety of hematological or chemical diagnostic procedures on very small quantities of blood. Because of this, a patient's finger, earlobe, or infant's heel may be punctured and a very small quantity of blood rapidly collected into a microcollection container for such testing. Such arrangements obviate the need to withdraw venous blood from patients. However, such collection arrangements must be such that the blood is rapidly collected prior to any coagulation thereof. In the past, prior to the scoop collector disclosed in the above-noted U.S. Pat. No. 4,397,318, a cap or top arrangement was configured to fit on the top of a microcollection container with the top having an integral capillary tube for engaging the puncture and transferring blood to the container. However, with such an arrangement, the tip of the capillary tube had to be arranged precisely adjacent the puncture wound and the entire apparatus had to be so positioned that the blood flow along the bottom surface of the tubular microcollection container moved continuously in order to engage the surface of the container. Otherwise, if a precise positioning was not carried out, capillary action was not initiated or slowed with subsequent clotting. Representative such collectors are taught in U.S. Pat. No. 4,024,857, issued May 24, 1977.
One problem with the scoop collector taught and claimed in U.S. Pat. No. 4,397,318, although the arrangement taught therein is highly efficient for the rapid collection of a blood sample into a microcollection container, is the fact that because of the very rapid collection of blood by the scoop collector, the separate blood passage in the collector becomes somewhat occluded by the blood passing therethrough and there is "hang-up" on the walls thereof by capillary action. While this phenomenon is only momentary, it can delay blood collection in situations where the technician is, for example, attempting to take a blood sample, from a screaming, wiggly baby.
With this invention, by contrast, a scoop arrangement is incorporated into a blood microcollection assembly in such a way that the scoop collector does not have a separate vane or wall separating the air vent passage in the collector from the blood passage. It has, instead only longitudinally extending ribs extending only part way into the combined blood/air passage. The ribs contain blood flow so that the blood does not touch the walls of the combined passage through the entire circumferential extent thereof. For this reason, capillary action causing blood "hang-up" does not take place and blood flows rapidly through the passage. This in turn reduces blood sample waste in the very small total quantities involved, resulting in a larger specimen yield. Moreover, such an arrangement reduces the need for incorporating expensive wetting agents in the collector devices of the invention.
Other objects and advantages of this invention will be apparent from the following description, the accompanying drawings and the appended claims.